Storage enclosures serving for example as pyrotechnic and hybrid gas generators containing propergol for inflation of airbags are known from prior art. However, propergols are expensive products which give off effluents and hot particles which need filtering. It is therefore useful to propose storage enclosures which use a less expensive raw material and produce neither particles nor effluents. Prior art describes storage enclosures using gaseous oxygen and gaseous hydrogen which are each confined in a chamber which has a metal wall or are both confined in a single gas reserve. A problem of these enclosures is that the hydrogen confined in the metal chamber tends, when in contact with steel, to is disassociate such that it may escape by diffusion through the metal wall and recombine on the other side of the wall. The enclosures may lose their inflation capabilities and no longer meet the performance criteria specified by vehicle manufacturers.
Patent specification US 2010/0024926 describes a metal coated with a protective layer formed by galvanisation of Zinc to protect the metal from hydrogen with the object of increasing the metal's resistance to delayed fracture. In contrast, patent specification U.S. Pat. No. 7,514,153 describes a process of coating a metal surface which consists in plating a Zinc-Nickel alloy on the surface to provide protection against hydrogen and therefore against corrosion, preventing embrittlement due to release of hydrogen when the process is employed. However, these specifications relate primarily to embrittlement of the metal on which the protective layer is formed and offer no solution to the hydrogen tightness problem described above. Moreover, these processes may give rise to emissions which degrade the welds which may subsequently be made on the surfaces treated.